title: Prognostic implications of radioiodine avidity and serum thyroglobulin in differentiated thyroid carcinoma with distant metastasis.
abstract: BACKGROUND
  Although differentiated thyroid carcinoma (DTC) rarely develops distant metastases, the present study was performed to evaluate factors that affect the survival of patients with DTC who present with distant metastasis.
  
  
  METHODS
  Among 4,989 patients who underwent thyroid surgery for DTC, 82 presenting with distant metastasis were analyzed. Based on radioiodine ((131)I) avidity and the thyroid-stimulating hormone-stimulated serum thyroglobulin (sTg) level at the time of metastasis, patients were divided into three groups: group 1 ((131)I uptake + sTg ≤ 215 ng/mL, n = 46), group 2 ((131)I uptake + sTg > 215 ng/mL, n = 24), group 3 (no (131)I uptake, n = 12). Disease-specific survival (DSS) was estimated using the Kaplan-Meier method. Factors predicting the outcome were evaluated using Cox proportional hazard regression analysis.
  
  
  RESULTS
  The age of patients (p = 0.04), frequency of follicular thyroid carcinoma (p = 0.002), tumor size (p < 0.001), and number of multiple metastatic sites (p = 0.004) differed significantly among the groups. With a median follow-up after surgery of 72 months, the 5- and 10-year DSSs for all patients were 84 and 69 %, respectively. The predictors of survival were age (p = 0.004), symptoms at the time of presentation (p = 0.045), histology (p = 0.01), sites of metastasis (p = 0.03), and (131)I avidity and sTg level at the time of metastasis (p = 0.002). In the multivariate analysis, age, histology, and (131)I avidity and sTg level at the time of metastasis remained significant factors for survival.
  
  
  CONCLUSIONS
  Certain DTC patients with distant metastasis demonstrate favorable outcomes dependent on age, histology, and (131)I avidity and sTg level at the time of metastasis.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, #50 Irwon-dong, Gangnam-gu, Seoul, 135-710, Korea, eyedr53@gmail.com.
authors.forename: Hye Jeong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Ji In
authors.initials: JI
authors.lastname: Lee
authors.forename: Na Kyung
authors.initials: NK
authors.lastname: Kim
authors.forename: Yong-Ki
authors.initials: YK
authors.lastname: Min
authors.forename: Sun Wook
authors.initials: SW
authors.lastname: Kim
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Chung
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000097:blood / Q000175:diagnosis* / Q000401:mortality / Q000601:surgery; D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002277:Carcinoma / Q000097:blood / Q000175:diagnosis / Q000401:mortality / Q000601:surgery; D002291:Carcinoma, Papillary; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009362:Neoplasm Metastasis; D011379:Prognosis; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D016019:Survival Analysis; D013954:Thyroglobulin / Q000097:blood*; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000401:mortality / Q000601:surgery; D013965:Thyroidectomy; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D015415:Biomarkers; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D013954:Thyroglobulin